While cutting out processed foods, excess sugar, and unhealthy fats can improve a person's overall health, too much restriction can be quite harmful, according to the US Department of Health and Human Services (HHS).

Like many trendy diets today, including keto and Whole 30, the Daniel Fast limits dieters' food options. And although cutting out processed foods, excess sugar, and unhealthy fats can improve a person's overall health, too much restriction can be quite harmful, according to the US Department of Health and Human Services (HHS).

"Diets that severely restrict calories or the types of food you eat usually don't lead to lasting weight loss and may not provide all the nutrients you need," the HHS explained on its website. The HHS added that such diets aren't easy to maintain over time, which could explain why the Daniel Diet is only recommended for 21 days.

To stay healthy, a balanced diet of protein, carbohydrates, and healthy fats is the way to go

The diet requires people to eat a mix of healthy fats like nuts and salmon, fruits, vegetables, and whole grains, and limit processed foods and sugar. According to the Mayo Clinic, this type of eating plan can help lower bad cholesterol and promote heart health, all while keeping dieters satisfied in the long run.